1. Field of the Invention
The present invention relates to a sheet feeding device provided in a recording apparatus such as a facsimile machine, a copying machine, or a printer. More specifically, the invention relates to such a sheet feeding device removably equipped with a sheet cassette in which recording sheets are accommodated, wherein paper jamming is prevented at a time when the sheet cassette is taken out of a main body of the apparatus.
2. Discussion of Related Art
A general recording apparatus such as a facsimile machine, a copying machine or a printer conventionally includes a recording device configured to record an image on a recording sheet, a sheet feeding device configured to feed the recording sheets one by one from a sheet cassette to the recording device, and a sheet discharging device configured to discharge the recording sheet from the recording device. As such a sheet feeding device, there is known one including: a sheet cassette which accommodates the recording sheets; a sheet-supply conveyance path through which each recording sheet is conveyed from the sheet cassette to the recording device; a pickup roller; a feed roller disposed downstream of the pickup roller on the conveyance path; and a separation roller which forms a pair with the feed roller. The pickup roller is configured to come into pressing contact with an uppermost one of the recording sheets accommodated so as to be stacked on the sheet cassette. The separation roller is configured to come into pressing contact with the feed roller. Further, the feed roller is configured to rotate so as to feed each of the recording sheets in a sheet feed direction along the conveyance path while the separation roller is configured to rotate so as to send the recording sheet back in a direction opposite to the sheet feed direction. In the thus constructed sheet feeding device, each of the recording sheets accommodated in the sheet cassette is sent to the conveyance path by the rotation of the pickup roller, and one recording sheet separated from the other sheets by the rotations of the feed roller and the separation roller is fed in the sheet feed direction along the conveyance path.
In the sheet feeding device described above, the sheet cassette is generally disposed in the main body of the recording apparatus so as to be attachable to and detachable from the main body. In replenishing the sheet cassette with the recording sheets, the sheet cassette installed in the main body of the recording apparatus is once taken out of the main body, and the sheet cassette is inserted back into the main body after the recording sheets have been accommodated in the sheet cassette for replenishment. In a general sheet feeding device, the direction in which the sheet cassette is moved at a time when the sheet cassette is taken out of the main body is orthogonal to a direction in which the recording sheet is sent from the sheet cassette by the pickup roller. Accordingly, where the recording sheet is receiving a pressure from the pickup roller, the feed roller or the separation roller at a time when the sheet cassette is taken out of the main body, a part of the recording sheet that is receiving the pressure from the roller may be torn as a result of failure to follow the movement of the sheet cassette or the recording sheet may remain in the main body to cause a malfunction of the apparatus. In view of this, there is proposed a structure in which the pickup roller and the separation roller are separated away from the recording sheet at a time when the sheet cassette is taken out of the main body, as disclosed in the following Patent Literature 1.
As a sheet feeding device having the structure described above, there is known a sheet feeding device in which cutting off a current supply to a solenoid triggers the separation roller to separate away from the feed roller. The disclosed sheet feeding device is equipped with a pressure release solenoid configured to move the separation roller. When the apparatus is operating, the current supply to the pressure release solenoid is turned on, whereby the separation roller is brought into pressing contact with the feed roller. When the apparatus stops operating, the current supply to the solenoid is turned off, whereby the separation roller is controlled to be separated away from the feed roller.